Preheat the oven to 350°F/175°C.
Grease two 18cm cake tins with coconut oil and line the bases with parchment paper.
In a large bowl, whisk the flaxseed, coconut oil and maple syrup/coconut nectar until combined.
Add the banana and almond milk and whisk again for several minutes until everything is fully combined.
Add the coconut sugar, salt, baking soda, cacao, almond flour, rice flour and vanilla (if using) and stir until mixture is combined and lump-free.
Divide the mixture evenly between the two cake tins.
Bake for approximately 45-60 minutes (until a knife comes out of the centre of each cake clean).
Turn the cakes out onto a wire rack and leave to cool completely.